Magnetron sputter devices are characterized by crossed electric and magnetic fields in an evacuated chamber into which an inert, ionizable gas, such as argon, is introduced. The gas is ionized by electrons accelerated by the electric field. The magnetic field confines the ionized gas, which forms a plasma in proximity to a target structure. The gas ions strike the target structure, causing emission of atoms that are incident on a workpiece, typically a substrate in a coating process. Generally, the magnetic field is established by a permanent magnet structure, although increasingly electromagnetic devices are being employed for this purpose. In coating applications, the magnetron sputtering devices are frequently employed to deposit metals in the manufacture of electronic, integrated circuit type devices. It is also known to deposit magnetic materials in the manufacture of high density magnetic discs of a type used for magnetic disc memories.
In prior art magnetron sputtering devices, uniform coating thickness across a substrate was obtained by moving the substrates during coating. Moving the substrates also assisted in obtaining optimum step coverage, i.e., step type transitions from one coating to another. Of course there are many problems in moving a substrate during operation of a sputtering device. It is also desirable in certain instances to co-deposit different materials, particularly materials which are difficult or impossible to alloy. These materials are not adapted to be located on a single target. In the past, co-depositing has been performed by moving a substrate relative to several targets, each having a planar configuration. In all instances, it is desirable to operate the sputtering device at as high a rate as possible.
It is, accordingly, an object of the present invention to provide a new and improved magnetron sputtering device.
A further object of the invention is to provide a magnetron sputtering device wherein material emitted from a relatively large target area is incident uniformly on a large area workpiece.
Another object of the invention is to provide a new and improved sputtering device having a relatively high speed operating rate.
Another additional object is to provide a new and improved sputtering device capable of providing step coverage on a large area workpiece without moving the workpiece.